package com.hmdp.service.impl;

import cn.hutool.core.bean.BeanUtil;
import com.baomidou.mybatisplus.extension.service.impl.ServiceImpl;
import com.hmdp.dto.Result;
import com.hmdp.entity.SeckillVoucher;
import com.hmdp.entity.VoucherOrder;
import com.hmdp.mapper.UserMapper;
import com.hmdp.mapper.VoucherOrderMapper;
import com.hmdp.service.ISeckillVoucherService;
import com.hmdp.service.IVoucherOrderService;
import com.hmdp.utils.RedisIdWorker;
import com.hmdp.utils.UserHolder;
import org.redisson.api.RedissonClient;
import org.springframework.aop.framework.AopContext;
import org.springframework.beans.factory.annotation.Autowired;
import org.springframework.core.io.ClassPathResource;
import org.springframework.data.redis.connection.stream.*;
import org.springframework.data.redis.core.StringRedisTemplate;
import org.springframework.data.redis.core.script.DefaultRedisScript;
import org.springframework.stereotype.Service;
import org.springframework.transaction.annotation.Transactional;

import javax.annotation.PostConstruct;
import java.time.Duration;
import java.time.LocalDateTime;
import java.util.Collections;
import java.util.List;
import java.util.Map;
import java.util.concurrent.ArrayBlockingQueue;
import java.util.concurrent.BlockingQueue;
import java.util.concurrent.ExecutorService;
import java.util.concurrent.Executors;

/**
 * <p>
 *  服务实现类
 * </p>
 *
 * @author 虎哥
 * @since 2021-12-22
 */
@Service
public class VoucherOrderServiceImpl extends ServiceImpl<VoucherOrderMapper, VoucherOrder> implements IVoucherOrderService {

    @Autowired
    ISeckillVoucherService seckillVoucherService;
    @Autowired
    private RedisIdWorker redisIdWorker;
    @Autowired
    private UserMapper userMapper;
    @Autowired
    private StringRedisTemplate stringRedisTemplate;

    @Autowired
    private RedissonClient redissonClient;

    private static final DefaultRedisScript<Long> SECKILL_SCRIPT;

    // 异步处理线程池
    private static final ExecutorService SECKILL_ORDER_EXECUTOR = Executors.newSingleThreadExecutor();


    private BlockingQueue<VoucherOrder> orderTasks = new ArrayBlockingQueue<>(1024 * 1024);

    private IVoucherOrderService proxy;


    @PostConstruct
    private void init() {
        SECKILL_ORDER_EXECUTOR.submit(new VoucherOrderHandler());
    }

    static {
        SECKILL_SCRIPT = new DefaultRedisScript<>();
        SECKILL_SCRIPT.setLocation(new ClassPathResource("seckill.lua"));
        SECKILL_SCRIPT.setResultType(Long.class);
    }


    // 普通秒杀
    public Result seckillVoucher1(Long voucherId) {
        SeckillVoucher voucher = seckillVoucherService.getById(voucherId);
        if (voucher.getBeginTime().isAfter(LocalDateTime.now())) {
            return Result.fail("秒杀尚未开始！");
        }
        if (voucher.getEndTime().isBefore(LocalDateTime.now())) {
            return Result.fail("秒杀已经结束！");
        }
        if (voucher.getStock() < 1) {
            return Result.fail("库存不足");
        }

        boolean success = seckillVoucherService.update().setSql("stock = stock - 1").eq("voucher_id", voucherId).gt("stock", 0).update();
        if (!success) {
            return Result.fail("库存不足！");
        }
        VoucherOrder voucherOrder = new VoucherOrder();
        long orderId = redisIdWorker.nextId("order");
        voucherOrder.setId(orderId);
        Long userId = UserHolder.getUser().getId();
        voucherOrder.setUserId(userId);
        voucherOrder.setVoucherId(voucherId);
        save(voucherOrder);

        return Result.ok(orderId);
    }

//    @Override
//    public Result seckillVoucher(Long voucherId) {
//        SeckillVoucher voucher = seckillVoucherService.getById(voucherId);
//        if (voucher.getBeginTime().isAfter(LocalDateTime.now())) {
//            return Result.fail("秒杀未开始！");
//        }
//        if (voucher.getEndTime().isBefore(LocalDateTime.now())) {
//            return Result.fail("秒杀已经结束！");
//        }
//        if (voucher.getStock() < 1) {
//            return Result.fail("库存不足");
//        }
//
//        Long userId = UserHolder.getUser().getId();
//        //创建锁对象(新增代码) 换用分布式锁
////        SimpleRedisLock lock = new SimpleRedisLock(stringRedisTemplate,"order:" + userId);
//        RLock lock = redissonClient.getLock("order:" + userId);
//        boolean isLock = lock.tryLock();
//        if(!isLock){
//            return Result.fail("不允许重复下单");
//        }
//
//        try {
//            // 获取代理对象（事务）
//            IVoucherOrderService proxy = (IVoucherOrderService) AopContext.currentProxy();
//            return proxy.createVoucherOrder(voucherId);
//        } finally {
//            //释放锁
//            lock.unlock();
//        }
//    }

    @Override
    public Result seckillVoucher(Long voucherId) {
        Long userId = UserHolder.getUser().getId();
        long orderId = redisIdWorker.nextId("order");

        Long result = stringRedisTemplate.execute(
                SECKILL_SCRIPT,
                Collections.emptyList(),
                voucherId.toString(), userId.toString(), String.valueOf(orderId)
        );


        int r = result.intValue();
        if (r != 0) {
            return Result.fail(r == 1 ? "库存不足" : "不能重复下单");
        }

        VoucherOrder voucherOrder = new VoucherOrder();
        voucherOrder.setId(orderId);
        voucherOrder.setUserId(userId);
        voucherOrder.setVoucherId(voucherId);
        orderTasks.add(voucherOrder);
        // 获取代理对象
        proxy = (IVoucherOrderService) AopContext.currentProxy();
        return Result.ok(orderId);
    }

    @Transactional
    public void createVoucherOrder(VoucherOrder voucherOrder) {
        Long userId = voucherOrder.getUserId();
        Integer count = query().eq("user_id", userId).eq("voucher_id", voucherOrder.getVoucherId()).count();
        if (count > 0) {
            log.error("该用户已经购买过了！");
        }

        boolean success = seckillVoucherService.update().setSql("stock = stock -1").eq("voucher_id", voucherOrder.getVoucherId()).gt("stock", 0).update();

        if (!success) {
            log.error("库存不足！");
        }
        save(voucherOrder);
    }


    // 用于线程池处理的任务
    // 当初始化完毕后，就会去从队列中去拿信息
    private class VoucherOrderHandler implements Runnable {


        //1.阻塞队列方式
//        @Override
//        public void run() {
//            while (true) {
//                try {
//                    VoucherOrder voucherOrder = orderTasks.take();
//                    handleVoucherOrder(voucherOrder);
//                } catch (Exception e) {
//                    log.error("处理订单异常", e);
//                }
//            }
//        }
//
//        private void handleVoucherOrder(VoucherOrder voucherOrder) {
//            Long userId = voucherOrder.getUserId();
//            RLock redissonClientLock = redissonClient.getLock("lock:order:" + userId);
//            boolean isLock = redissonClientLock.tryLock();
//            if (!isLock) {
//                //获取锁失败，直接返回失败或者重试
//                log.error("不允许重复下单！");
//                return;
//            }
//
//            proxy.createVoucherOrder(voucherOrder);
//
//        }

        @Override
        public void run() {
            log.debug("秒杀优化--流式消息队列方式");
            while (true){
                try {
                    // 1.获取消息队列中的订单信息 XREADGROUP GROUP g1 c1 COUNT 1 BLOCK 2000 STREAMS s1 >
                    // 从流 s1 中读取未处理的消息，属于消费组 g1，消费者 c1 以每次 1 条消息的速度读取，最多等待 2000 毫秒
                    List<MapRecord<String, Object, Object>> list = stringRedisTemplate.opsForStream().read(
                            Consumer.from("g1", "c1"),
                            StreamReadOptions.empty().count(1).block(Duration.ofSeconds(2)),
                            StreamOffset.create("stream.orders", ReadOffset.lastConsumed())
                    );
                    if (list==null||list.isEmpty()) {
                        continue;
                    }

                    MapRecord<String, Object, Object> record = list.get(0);
                    Map<Object, Object> value = record.getValue();
                    VoucherOrder voucherOrder = BeanUtil.fillBeanWithMap(value, new VoucherOrder(), true);

                    createVoucherOrder(voucherOrder);
                    //确认消息XACK
                    stringRedisTemplate.opsForStream().acknowledge("s1","g1",record.getId());
                } catch (Exception e) {
                    log.error("处理订单异常",e);
                    handlePendingList();
                }

            }
        }

        private void handlePendingList() {
            while (true){
                try {
                    // 1.获取消息队列中的订单信息 XREADGROUP GROUP g1 c1 COUNT 1 BLOCK 2000 STREAMS s1 >
                    // 从流 s1 中读取未处理的消息，属于消费组 g1，消费者 c1 以每次 1 条消息的速度读取，最多等待 2000 毫秒
                    List<MapRecord<String, Object, Object>> list = stringRedisTemplate.opsForStream().read(
                            Consumer.from("g1", "c1"),
                            StreamReadOptions.empty().count(1),
                            StreamOffset.create("stream.orders", ReadOffset.from("0"))
                    );
                    if (list==null||list.isEmpty()) {
                        continue;
                    }

                    MapRecord<String, Object, Object> record = list.get(0);
                    Map<Object, Object> value = record.getValue();
                    VoucherOrder voucherOrder = BeanUtil.fillBeanWithMap(value, new VoucherOrder(), true);

                    createVoucherOrder(voucherOrder);
                    //确认消息XACK
                    stringRedisTemplate.opsForStream().acknowledge("s1","g1",record.getId());
                } catch (Exception e) {
                    log.error("处理pending订单消息异常",e);
                    try {
                        Thread.sleep(20);
                    } catch (InterruptedException ex) {
                        e.printStackTrace();
                    }
                }

            }
        }
    }


}
